JP3404960B2 - Loudspeaker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker communication device capable of making a call using a microphone and a speaker without holding a handset.

[0002]

2. Description of the Related Art Conventionally, an intercom base unit installed in a living room or the like in a dwelling unit and an intercom subunit installed in a front door or a doorway are provided, and a space between a resident in the dwelling unit and a visitor at the doorway or the doorway. There is known an intercom device that enables two-way simultaneous communication via a two-line communication line. In this conventionally known intercom device, the intercom sub-unit has a microphone and a speaker instead of a handset, and is capable of convenient voice communication without the need to hold an object. However, the intercom base unit has a so-called handset including a transmitter and a receiver which are held by a hand and addressed to the mouth and the ear.

However, in recent years, even in the intercom base unit, a voice communication device called a hands-free intercom, which has a microphone and a speaker incorporated in the main body similarly to the intercom subunit and is capable of convenient voice communication, is known. Is also commercially available.

By the way, in the loudspeaker communication device called a hands-free intercom as described above, a part of the sound output from the speaker of the intercom base unit enters the microphone of the intercom base unit and the communication line Is output to the speaker of the intercom slave unit, enters the microphone of the intercom slave unit, and outputs again from the speaker of the intercom master unit, forming a closed loop, which easily causes an obstacle such as howling or echo.

Therefore, in the conventional voice communication device,
Received signal level (call signal level from the intercom subunit)
Is higher than the transmission signal level (call signal level from the intercom base unit), the loss amount of the reception channel is decreased and the loss amount of the transmission channel is increased, and the transmission signal level is the reception signal level. A voice switch circuit that reduces the amount of loss in the transmission path and increases the amount of loss in the reception path when the level is higher than the level, and keeps the total amount of loss in the transmission direction and the reception direction almost constant. A so-called howling suppression circuit is provided to ensure a clear call without causing a call disturbance such as howling or echo.

FIG. 5 is a block diagram showing an outline of a conventional voice communication device equipped with the voice switch circuit as described above. As shown in FIG. 5, the voice communication device includes an intercom base unit 1 and an intercom subunit 2.

The intercom base unit 1 comprises a voice switch circuit 10, a sound-proof sound circuit 11, a microphone 12, a speaker 13, a microphone preamplifier 14, a speaker amplifier 15, and a control unit 16. Doorphone subunit 2
Includes an anti-sidephone circuit 20, a microphone 21, a speaker 22, a microphone preamplifier 23, and a speaker amplifier 24.

As described above, the voice switch circuit 10 is for ensuring a clear call without causing a call disturbance such as howling or echo, and is a transmission signal level detection circuit 10a.
, The reception signal level detection circuit 10b, and the comparison controller 10
c, a transmission channel variable insertion loss circuit 10d, and a reception channel variable insertion loss circuit 10e. The transmission signal level detection circuit 10a includes a microphone 12 and a microphone preamplifier 1
The transmission signal level output to the transmission path through 4 is detected. The reception signal level detection circuit 10b is used for the intercom subunit 2
To the reception signal level output to the reception path through the two-line communication line L and the protection-side sound circuit 11.

The comparison controller 10c compares the transmission signal level detected by the transmission signal level detection circuit 10a with the reception signal level detected by the reception signal level detection circuit 10b, and the transmission signal level is the reception. The higher the signal level, the smaller the loss amount of the variable transmission path insertion loss circuit 10d and the higher the loss amount of the variable reception path insertion loss circuit 10e, and the higher the reception signal level than the transmission signal level. The larger the value, the smaller the loss amount of the reception channel variable insertion loss circuit 10e and the more the loss amount of the transmission channel variable insertion loss circuit 10d, the loss amount of the transmission channel variable insertion loss circuit 10d and the reception channel variable insertion. The loss circuit 10e operates so that the total sum with the loss amount of the loss circuit 10e is always kept substantially constant. The transmission path variable insertion loss circuit 10d attenuates the level of the transmission signal passing through the transmission path by the attenuation amount based on the instruction from the comparison controller 10c. The reception channel variable insertion loss circuit 10e attenuates the reception signal level passing through the reception channel with an attenuation amount based on an instruction from the comparison controller 10c.

The sound-proof side sound circuit 11 includes the intercom subunits 2 to 2
The received signal coming through the communication line L of the line is guided only to the receiving path side, and the transmitted signal coming from the sending path from the microphone 12 through the microphone preamplifier 14 and the sending path variable insertion loss circuit 10d is two lines. It is guided only to the direction of the intercom subunit 2 via the communication line L of, and is called a so-called 2-wire 4-wire conversion circuit. The control unit 16 is controlled by a microprocessor, monitors the presence / absence signal of a visitor from the intercom subunit 2, and supplies a drive voltage to the intercom subunit 2 when there is a visitor. Plays a function.

The protection sound circuit 20 transmits a transmission signal (reception signal when viewed from the intercom slave unit) coming from the intercom base unit 1 via the two-line communication line L to the speaker 22 side via the speaker amplifier 24. In addition to guiding only, the reception signal (the transmission signal when seen from the intercom subunit) that comes from the microphone 21 through the microphone preamplifier 23 is guided only to the intercom master unit 1 via the two-line communication line L. It is called a so-called 2-wire / 4-wire conversion circuit.

Therefore, the conventional voice communication device as described above operates as follows. That is, the visitor at the entrance pushes the visitor button (not shown) of the intercom subunit 2. Then, control unit 16 detects the presence of a visitor and outputs a drive voltage to intercom subunit 2, and intercom subunit 2 is activated. Therefore, the visitor is a doorphone subunit 2
When talking to the microphone 21, the voice of the visitor is picked up by the microphone 21, amplified by the microphone preamplifier 23, and reaches the protection side sound circuit 20. The voice of the visitor who has reached the protection side sound circuit 20 is output only to the call line L side without being output to the speaker amplifier 24, reaches the protection side sound circuit 11, and is output from the protection side sound circuit 11 to the receiving side. To be done.

Usually, when a visitor is speaking, the resident in the dwelling does not speak. Therefore, since the reception signal level of the comparison controller 10c is higher than the transmission signal level, the sum of the loss amount of the transmission channel variable insertion loss circuit 10d and the loss amount of the reception channel variable insertion loss circuit 10e is constant. While keeping
The loss amount of the receiving channel variable insertion loss circuit 10e is reduced and the loss amount of the transmitting channel variable insertion loss circuit 10d is increased. Therefore, although the visitor can hardly hear the unnecessary sound in the dwelling unit from the speaker 22, the resident can hear the visitor's voice with a loud sound from the speaker 13 and, as a closed loop in which howling and echo occur. Since there is no gain change, howling and echo are not generated, and clear communication can be performed without causing a call disturbance such as howling or echo.

When the resident speaks, the same reasoning applies,
Although the resident can hardly hear the unnecessary sound at the entrance from the speaker 13, the visitor hears the resident's voice through the speaker 22.
Therefore, since there is no change in the gain as a closed loop in which howling or echo occurs, howling or echo does not occur, and clear communication can be performed without causing a call disturbance of howling or echo.

[0015]

However, in the conventional loudspeaker communication device as described above, the ambient noise level on the side of the intercom base unit installed in the dwelling unit is relatively quiet and stable throughout the day. On the other hand, the ambient noise level on the side of the intercom that is installed outdoors such as at the front door or at the doorway differs between day and night due to the running noise of the automobile and the operating noise of the factory.

For example, in the daytime, since the ambient noise level on the intercom subunit is high, the intercom master unit hears the noise on the intercom subunit side and the voice of the visitor loudly, and the intercom subunit on the intercom subunit side hears the residents. Voice is buried in the noise and hard to hear, and the comparison controller of the voice switch circuit has a constantly high ambient noise level on the side of the intercom subunit, which increases the loss amount of the transmission path variable insertion loss circuit and increases the reception channel variable insertion loss circuit. The loss amount of resident may remain reduced and the resident's voice may not be heard.

At night, the voice level of the visitor becomes low due to the quietness of the ambient noise, so that the intercom base unit side cannot hear the voice of the visitor and the doorphone subunit is a resident. Becomes very loud and the conversation leaks to the next house. Furthermore, if the conversation between the resident and the visitor is interrupted, there is a problem that sound other than the voice of the resident on the intercom base unit, such as the sound of the TV or stereo, leaks to the visitor. It was

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an appropriate transmission / reception level at any time according to the ambient noise level of the intercom subunit. Even if the conversation between the resident and the visitor is interrupted, the resident is to provide an excellent loudspeaker communication device that can hear the sound (footsteps, running sound of the car, etc.) of the intercom subunit. .

[0019]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an intercom master unit and an intercom slave unit which are connected to each other via a communication line. The intercom base unit is installed indoors and has a microphone, a speaker, a transmission path variable insertion loss circuit that compares the transmission signal level and the reception signal level, and changes the loss amount according to the comparison result. A voice switch circuit having a variable reception path insertion loss circuit, and an intercom subunit is installed at a front door or the like and has a microphone and a speaker. Sometimes, the noise detector that periodically detects the noise level on the intercom subunit side from the microphone of the intercom subunit, the transmission channel variable amplification circuit located after the transmission channel variable insertion loss circuit, And characterized in that the transmission path gain varying means for varying the gain of the transmission path variable amplifying circuit in response to the intercom slave unit side noise levels obtained for detector, both provided <br/> the intercom master unit To do.

According to the second aspect of the present invention, the interphone master unit includes an intercom master unit and an intercom slave unit which are connected to each other via a communication line. The intercom master unit is installed indoors and includes a microphone and a speaker. A voice switch circuit having a transmission channel variable insertion loss circuit and a reception channel variable insertion loss circuit for comparing the transmission signal level and the reception signal level and changing the loss amount according to the comparison result, The intercom subunit is installed at the entrance or the like and has a microphone and a speaker. In a loudspeaker communication device, the noise level of the intercom subunit is periodically detected from the microphone of the intercom subunit during non-call. The noise detection section, the reception path variable amplification circuit located in the preceding stage of the reception path variable insertion loss circuit, and the reception path can be received depending on the noise level on the doorphone handset obtained by the noise detection section. A reception path gain varying means for varying the gain of the amplifier circuit, both of which being provided in the intercom master unit.

According to another aspect of the present invention, the intercom master unit includes an intercom master unit and an intercom slave unit that are connected to each other via a communication line. The intercom master unit is installed indoors and includes a microphone and a speaker. A voice switch circuit having a transmission channel variable insertion loss circuit and a reception channel variable insertion loss circuit for comparing the transmission signal level and the reception signal level and changing the loss amount according to the comparison result, The intercom subunit is installed at the entrance or the like and has a microphone and a speaker. In a loudspeaker communication device, the noise level of the intercom subunit is periodically detected from the microphone of the intercom subunit during non-call. Noise detector, variable transmission path amplifier circuit located after the variable transmission path insertion loss circuit, and variable reception path amplifier circuit located before the variable insertion loss circuit for reception path And a gain reciprocal varying means for varying inconsistently the gain of the transmission path variable amplification circuit and the reception path variable amplifying circuit in response to the intercom slave unit side noise levels obtained noise detector, both the intercom master unit It is characterized by being provided.

According to the fourth aspect of the invention, when both the transmission signal level and the reception signal level are below a predetermined level, the loss amount of the transmission channel variable insertion loss circuit is maximized and the reception channel variable. Minimize the loss of the insertion loss circuit,
In addition, it is characterized in that a sound collecting means is added to minimize the gain of the variable transmission path amplifier circuit and maximize the gain of the variable reception path amplifier circuit.

According to the fifth aspect of the invention, when the noise detecting section periodically detects the noise level on the doorphone handset side from the microphone of the doorphone handset during a non-call, the variable transmission path amplifier and the reception It is characterized in that a sound leakage preventing means for minimizing the gain with the variable path amplifier circuit is added.

[0024]

With the above construction, in the invention according to the first aspect, the noise detecting section periodically causes noise from the microphone of the intercom sub-unit to the intercom sub-unit side noise during a non-call without a visitor. The level is detected. Then, when there is a visitor, the transmission path gain varying means, according to the noise level on the doorphone subunit side stored in the noise detector, when the noise level on the doorphone subunit side is high, the transmission channel variable amplification is performed. The gain of the circuit can be increased to make the resident's voice louder, and the visitor can hear the resident's voice at a level comparable to that of the intercom subunit side noise, which enables comfortable listening.

According to the second aspect of the present invention, the noise detection unit periodically detects the doorphone handset side noise level from the microphone of the doorphone handset when there is no call with no visitors. Then, when there is a visitor, the reception path gain varying means, in accordance with the doorphone subunit side noise level stored in the noise detector, when the doorphone subunit side noise level is high, the reception channel variable amplifier circuit By lowering the gain and increasing the gain of the reception path variable amplification circuit when the noise level on the doorphone subunit side is low, the output of the reception channel variable amplification circuit can be set whether the noise level on the doorphone subunit side is high or low. It is possible to keep the voice level of the visitor (the voice level of the visitor in the preceding stage of the variable transmission path insertion loss circuit) to be constant. Therefore, the voice switch circuit keeps the loss amount of the transmission path variable insertion loss circuit always high due to the influence of the noise level on the doorphone subunit, and the visitor can hear the resident's voice in a sufficiently loud voice. The inconvenience of not being able to be prevented can be prevented, and comfortable listening is possible.

According to the third aspect of the invention, the noise detecting section periodically detects the doorphone handset side noise level from the microphone of the doorphone handset when there is no call with no visitors. Then, when there is a visitor, the gain reciprocal variable means makes the gains of the transmission channel variable amplification circuit and the reception channel variable amplification circuit conflict with each other in accordance with the noise level on the doorphone subunit side stored in the noise detection section. The gain is adjusted so that the total gain of the transmission path variable amplification circuit and the reception path variable amplification circuit is approximately constant, so it is clear that howling and echo call interference does not occur due to acoustic coupling from the speaker to the microphone. You can make calls.

According to another aspect of the invention, the sound collecting means maximizes the loss amount of the transmission path variable insertion loss circuit when both the transmission signal level and the reception signal level are below a predetermined level. In addition to minimizing the loss amount of the reception channel variable insertion loss circuit, and minimizing the gain of the transmission channel variable amplification circuit and maximizing the gain of the reception channel variable amplification circuit, When the conversation is interrupted, it is possible to make it easier for the resident to hear the sound of the visitor or the front door, and prevent the sound of the inside of the dwelling unit from leaking to the visitor at the front door.

According to the fifth aspect of the invention, the sound leakage preventing means transmits the sound when the noise detecting unit periodically detects the noise level on the doorphone subunit side from the microphone of the doorphone subunit when not in a call. Since the gain between the variable path amplifier circuit and the receiving path variable amplifier circuit is minimized, it is possible to prevent the intercom master unit from hearing the sound of the intercom slave unit and the sound of the dwelling unit leaking to the intercom slave unit. It can be prevented.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a voice communication device according to the present invention will be described below with reference to FIG. 1, a second embodiment will be described with reference to FIG. 2, and a third embodiment will be described with reference to FIG. The example and the fifth embodiment will be described in detail with reference to FIG.

[First Embodiment] FIG. 1 is a block diagram showing a main part of a voice communication device. In FIG. 1, the same parts as those of the voice communication device described in the related art are designated by the same reference numerals, and therefore detailed description of the same parts will be omitted.

The loudspeaker system shown in FIG. 1 is different from the conventional one in that the intercom master unit 1 has a transmission path gain varying means 16a, a noise detecting section 17, and a transmission path variable amplifying circuit 18a. And is provided. Noise detector 17
Detects the intercom subunit 2 side noise level from the microphone 21 of the intercom subunit 2 periodically during a non-call without a visitor and always stores the updated recent intercom subunit 2 noise level. The transmission path variable amplification circuit 18a is a variable amplifier inserted in a subsequent stage of the transmission path variable insertion loss circuit 10d, and includes the microphone 12 to the microphone preamplifier 14.
And the transmission signal coming through the transmission path variable insertion loss circuit 10d is amplified and output to the protection sound circuit 11.

The transmission path gain varying means 16a is provided in the control section 16. The transmission path gain varying means 16a reads out the updated recent intercom subunit 2 side noise level detected and stored by the noise detecting unit 17, and based on this intercom subunit 2 side noise level, the intercom subunit When the noise level on the second side is high, the gain of the transmission path variable amplifier circuit 18a is increased.

The voice communication device configured as described above operates as follows. That is, when there is no call with no visitors, the control unit 16 periodically supplies the drive voltage to the intercom subunit 2, and detects the ambient noise level on the intercom subunit 2 side with respect to the noise detecting unit 17. Instruct. The noise detection unit 17 periodically repeats the detection of the ambient noise level on the side of the intercom subunit 2 under the instruction of the control unit 16, and always stores the updated recent ambient noise level. Therefore, when the visitor presses a visitor button (not shown) included in the intercom subunit 2, the control unit 16 detects that the visitor button has been pressed, and the intercom subunit 2 is detected. A drive voltage is supplied and a control instruction is given to the transmission path gain varying means 16a.

Then, the transmission channel gain varying means 16a reads out the updated recent intercom subunit 2 side noise level stored in the noise detecting section 17, and based on this intercom subunit 2 side noise level, When the noise level on the side of the intercom subunit 2 is high, the gain of the transmission path variable amplification circuit 18a is increased to amplify the transmission signal and increase the voice of the resident. Therefore, the visitor hears the voice of the resident amplified to a level comparable to the noise on the side of the intercom subunit 2 to the speaker 22 of the intercom subunit 2.
It is possible to listen to from, and it becomes possible to listen comfortably.

Note that the transmission path gain varying means 16a does not use only the updated latest intercom subunit 2 side noise level stored in the noise detecting section 17, but a plurality of backward moving upwards. You may make it use the average value of the noise level of the doorphone subunit 2.

[Second Embodiment] FIG. 2 is a block diagram showing a main part of a voice communication device. In FIG. 2, the same parts as those of the voice communication device described in the related art are designated by the same reference numerals, and therefore detailed description of the same parts will be omitted.

The loudspeaker system shown in FIG. 2 is different from the conventional one in that the intercom base unit 1 is provided with a receiving path gain varying means 16b, a noise detecting section 17, and a receiving path variable amplifying circuit 18b. This is the configuration provided. Noise detector 17
Detects the intercom subunit 2 side noise level from the microphone 21 of the intercom subunit 2 periodically during a non-call without a visitor and always stores the updated recent intercom subunit 2 noise level. The receiving path variable amplification circuit 18b is a variable amplifier inserted in the preceding stage of the receiving path variable insertion loss circuit 10e, and reaches the protection side sound circuit 11 from the intercom subunit 2 through the communication line L and is output to the receiving path. Amplifies the signal,
Receiving channel variable insertion loss circuit 10e and speaker amplifier 15
It outputs to the speaker 13 via.

The receiving path gain varying means 16b is provided in the control section 16. The reception path gain varying means 16b reads the updated recent intercom subunit 2 side noise level detected and stored by the noise detector 17, and based on this intercom subunit 2 side noise level, the intercom subunit 2 is read. When the side noise level is high, the gain of the reception path variable amplification circuit 18b is lowered, and when the sidephone subunit 2 side noise level is low, the gain of the reception path variable amplification circuit 18b is increased.

The voice communication device configured as described above operates as follows. That is, when there is no call with no visitors, the control unit 16 periodically supplies the drive voltage to the intercom subunit 2, and detects the ambient noise level on the intercom subunit 2 side with respect to the noise detecting unit 17. Instruct. The noise detection unit 17 periodically repeats the detection of the ambient noise level on the side of the intercom subunit 2 under the instruction of the control unit 16, and always stores the updated recent ambient noise level. Therefore, when the visitor presses a visitor button (not shown) included in the intercom subunit 2, the control unit 16 detects that the visitor button has been pressed, and the intercom subunit 2 is detected. A drive voltage is supplied and a control instruction is given to the receiving channel gain varying means 16b.

Then, the reception path gain varying means 16b reads out the updated recent noise level of the intercom subunit 2 stored in the noise detecting section 17, and based on the noise level of the intercom subunit 2, the intercom When the noise level on the slave unit 2 side is high, the gain of the receiving channel variable amplifier circuit 18b is lowered, and when the noise level on the slave unit 2 side is low, the gain of the receiving channel variable amplifier circuit 18b is increased to change the receiving channel. The reception signal level in the preceding stage of the insertion loss circuit 10e, that is, the output level of the reception path variable amplification circuit 18b is maintained at a desired constant level regardless of whether the intercom subunit 2 side noise level is high or low.

Therefore, in the conventional voice communication device,
The ambient noise level on the intercom base unit 1 side is relatively quiet and stable throughout the day, while during the daytime,
Since the ambient noise level on the intercom subunit 2 side is high, the noise on the intercom subunit 2 side and the voice of the visitor are heard loud on the intercom master unit 1 side, and the residents' voice is buried in the noise on the intercom subunit 2. Not only is it difficult to hear, but since the comparison controller of the voice switch circuit always has a high ambient noise level on the side of the intercom subunit 2, the loss amount of the transmission channel variable insertion loss circuit 10d is increased to increase the loss amount of the reception channel variable insertion loss circuit 10e. Remains diminished, so you may not hear the residents
In addition, at night, the voice level of the visitor becomes low due to the quietness of ambient noise.
On the other side, the voice of the visitor is too quiet to hear, and on the side of the intercom subunit 2, the voice of the resident becomes very loud and the conversation leaks to the next house. Furthermore, the conversation between the resident and the visitor was interrupted. In such a case, there is a problem that sound other than the voice of the resident on the side of the intercom base unit 1 is leaked to the visitor, such as sound of a television or stereo, but these problems can be solved. That is, it is possible to comfortably listen without being affected by the ambient noise level on the doorphone subunit 2.

Further, the speaker 13 of the intercom base unit 1
The voice level of the visitor output from can be constantly maintained at a constant level that allows comfortable listening.

[Third Embodiment] FIG. 3 is a block diagram showing a main part of a voice communication device. In FIG. 3, parts that are the same as those of the voice communication device described in the related art are denoted by the same reference numerals, and therefore detailed description of the same parts is omitted.

The voice communication system shown in FIG. 3 is different from the conventional system in that the intercom master unit 1 has a gain reciprocal variable means 16c, a noise detection section 17, a variable transmission path amplifier circuit 18a. This is a configuration in which the reception path variable amplifier circuit 18b is provided.

The noise detecting unit 17 periodically detects the noise level of the intercom subunit 2 from the microphone 21 of the intercom subunit 2 when there is no call with no visitors, and the latest intercom subunit 2 is constantly updated. Memorize the side noise level. The transmission path variable amplification circuit 18a includes a transmission path variable insertion loss circuit 10d.
A variable amplifier inserted in the latter stage of the microphone 12
Amplifies a transmission signal coming from the microphone through the microphone preamplifier 14 and the transmission channel variable insertion loss circuit 10d and outputs the amplified signal to the protection side sound circuit 11. The receiving path variable amplification circuit 18b is a variable amplifier inserted in the preceding stage of the receiving path variable insertion loss circuit 10e, and reaches the protection side sound circuit 11 from the intercom subunit 2 through the communication line L and is output to the receiving path. The reception signal is amplified and output to the speaker 13 via the reception path variable insertion loss circuit 10e and the speaker amplifier 15.

The gain reciprocal variable means 16c is incorporated in the control section 16, and according to the noise level on the doorphone subunit 2 side stored in the noise detection section 7, the variable transmission path amplifier circuit 18a and the reception path. The gain with respect to the variable amplifier circuit 18b is varied in a reciprocal manner, and control is performed so that the total gain between the variable transmission amplifier circuit 18a and the variable amplification circuit 18b is substantially constant.

The loudspeaker communication apparatus configured as described above operates as follows. That is, when there is no call with no visitors, the control unit 16 periodically supplies the drive voltage to the intercom subunit 2, and detects the ambient noise level on the intercom subunit 2 side with respect to the noise detecting unit 17. Instruct. The noise detection unit 17 periodically repeats the detection of the ambient noise level on the side of the intercom subunit 2 under the instruction of the control unit 16, and always stores the updated recent ambient noise level. Therefore, when the visitor presses a visitor button (not shown) included in the intercom subunit 2, the control unit 16 detects that the visitor button has been pressed, and the intercom subunit 2 is detected. A drive voltage is supplied and a control instruction is given to the receiving channel gain varying means 16b.

Then, the gain reciprocal variable means 16c reads the updated recent intercom subunit 2 side noise level stored in the noise detector 17, and based on this intercom subunit 2 side noise level, the intercom subunit is read. When the noise level on the side of the door unit 2 is high, the gain of the variable amplifier circuit 18a for transmitting path is increased and at the same time the gain of the amplifying circuit for receiving path 18b is decreased. While decreasing the gain of the variable amplification circuit 18a and increasing the gain of the reception path variable amplification circuit 18b, the total gain of the transmission path variable amplification circuit 18a and the reception path variable amplification circuit 18b is always kept substantially constant.

Therefore, in the above-mentioned voice communication device,
"Speaker 13"->"Microphone12"->"Microphone preamplifier 14"->"Transmission path variable insertion loss circuit 10d"
→ "Variable transmission path amplifier circuit 18a" → "Side protection circuit 11"
→ "Call line L" → "Protective sound circuit 20" → "Speaker amplifier 24" → "Speaker 22" → "Microphone 21"
→ "Microphone preamplifier 23" → "Prevention side sound circuit 20" →
"Call line L" → "Reception channel variable amplification circuit 18b" → "Reception channel variable insertion loss circuit 10e" → "Speaker amplifier 1"
5 ”→“ Speaker 13 ”→“ Microphone 12 ”………
It is possible to maintain the gain of the closed loop, which is a cause of the obstacles such as howling and echo, without causing the obstacles such as howling and echo and still obtain a certain gain, to a value that allows a comfortable call.

[Fourth Embodiment] FIG. 4 is a block diagram showing a main part of a voice communication device. In FIG. 4, the above-mentioned [3rd
The same parts as those of the voice communication device described in the embodiment are designated by the same reference numerals, and detailed description of the same parts will be omitted.

A loudspeaker communication apparatus shown in FIG. 4 is a third embodiment.
What is different from the above is that the intercom base unit 1 is provided with a sound collection unit 16d.

The sound collecting means 16d is added to the controller 16. The sound collecting unit 16d transmits the transmission signal level detection circuit 1 via the comparison controller 10c of the voice switch circuit 10.
0a transmission signal level and reception signal level detection circuit 1
When the level of the receiving signal from 0b is recognized and both the level of the transmitting signal and the level of the receiving signal are below a predetermined level, the loss amount of the variable transmission path insertion loss circuit 10d is forcibly maximized and the receiving signal is received. The loss amount of the variable path insertion loss circuit 10e is minimized, the gain of the variable transmission path amplifier circuit 18a is minimized, and the gain of the variable reception path amplifier circuit 18b is maximized.

The voice communication device configured as described above operates as follows. That is, the operation is almost the same as that of the [third embodiment], except that the transmission detected by the transmission signal level detection circuit 10a, such as when the conversation between the resident and the visitor is interrupted. When the voice signal level and the voice signal level detected by the voice signal level detection circuit 10b are both lower than a predetermined level, the variable transmission path insertion loss circuit 10
The loss amount of d is maximized, the loss amount of the reception channel variable insertion loss circuit 10e is minimized, the gain of the transmission channel variable amplification circuit 18a is minimized, and the gain of the reception channel variable amplification circuit 18b is maximized. become.

Therefore, when the conversation between the resident and the visitor seems to be interrupted, it is possible to make it easier for the resident to hear the noise of the visitor and the front door, and also to make the interior of the dwelling unit accessible to the visitor at the front door. Leakage of noise can be prevented.

[Fifth Embodiment] This voice communication device is described in [Fourth Embodiment]
Since the configuration is almost the same as that of the embodiment], it will be described with reference to FIG. This loudspeaker communication device is different from that of [Fourth Embodiment] in that the interphone master unit 1 is provided with sound leakage prevention means.

The sound leakage prevention means (not shown) is the control unit 1.
6 is added. The sound leakage prevention unit compulsorily operates as the variable transmission path amplifier circuit 18a when the noise detector 17 periodically detects the noise level on the side of the intercom subunit 2 from the microphone 21 of the intercom subunit 2 during a non-call. The gain with the reception channel variable amplification circuit 18b is minimized, and the loss amount between the transmission channel variable insertion loss circuit 10d and the reception channel variable insertion loss circuit 10e is maximized.

The loudspeaker communication device configured as described above operates as follows. That is, the operation is almost the same as that of [Fourth Embodiment], except that the noise detector 17 is in the microphone 2 of the intercom subunit 2 when not in a call.
When the noise level on the doorphone subunit 2 side is periodically detected from 1, the gains of the transmission channel variable amplification circuit 18a and the reception channel variable amplification circuit 18b are compulsorily minimized, and the transmission channel variable insertion is performed. The loss amounts of the loss circuit 10d and the receiving path variable insertion loss circuit 10e are the operations that maximize each.

Therefore, even if a drive voltage is supplied to the intercom slave unit 2 in order to detect the noise level on the intercom slave unit 2, the sound of the intercom slave unit 2 can be heard by the intercom master unit 1 or the intercom master unit 1 can hear the noise. It is possible to prevent the noise in the dwelling unit on the machine 1 side from leaking to the intercom subunit 2 side.

[0059]

Since the loudspeaker system according to the present invention is constructed as described above, in the invention according to claim 1, the visitor is amplified to a size not defeated by the noise of the intercom subunit 2. The heard voice of the resident can be heard from the speaker 22 of the intercom subunit 2, which enables comfortable listening. In the invention according to claim 2, the voice switch circuit has ambient noise on the intercom subunit side in the daytime. Visitors can't hear the voice of the resident because of the influence of the sound of the resident, and at night, the voice switch circuit is affected by the voice switch circuit being affected by the quiet voice of the ambient noise on the side of the intercom. The voice of the visitor is too quiet to hear, or at night, the voice of the voice switch circuit is affected because the voice of the visitor speaks quietly due to the quietness of ambient noise on the side of the intercom. Sounds loud and next to Or conversation is accidentally leaked to, further, if such a conversation between the residents and the visitors is interrupted,
At night, the voice switch circuit is affected by the quietness of the ambient noise on the intercom subunit, which causes the sound of TVs and stereos other than the voice of the intercom main unit to leak to visitors. In the invention according to the third aspect, comfortable listening can be achieved by solving the problems, and the closed-loop gain that causes the obstacles such as howling and echo can be obtained without causing the obstacles such as howling and echo. According to the invention of claim 4, it is possible to obtain a certain amount of gain and keep the value at which comfortable calls are possible.
The invention according to claim 5, wherein when the conversation between the resident and the visitor seems to be interrupted, it is possible for the resident to easily hear the noise of the visitor or the front door, and to prevent the noise of the noise in the dwelling unit from being leaked to the visitor. In that case, even if a drive voltage is supplied to the intercom slave unit to detect the ambient noise level on the intercom slave unit side, the intercom master unit hears the sound of the intercom slave unit or the intercom master unit side sounds. It is possible to prevent an object sound in a dwelling unit from leaking to the intercom subunit, and it is possible to provide an excellent loudspeaker communication device that enables clear voice communication without being disturbed by ambient noise.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a first embodiment of a voice communication device according to the present invention.

FIG. 2 is a block diagram showing a main part of a second embodiment of a voice communication device according to the present invention.

FIG. 3 is a block diagram showing a main part of a third embodiment of the voice communication device according to the present invention.

FIG. 4 is a block diagram showing a main part of a fourth embodiment of the voice communication device according to the present invention.

FIG. 5 is a block diagram showing a main part of a conventional voice communication device.

[Explanation of symbols]

1 Intercom base unit Two-door intercom 10d Transmission path variable insertion loss circuit 10e Receiving channel variable insertion loss circuit 10 Voice switch circuit 12 microphones 13 speakers 16a Transmission path gain varying means 16b Receiving channel gain varying means 16c Gain reciprocal variable means 16d sound collection means 17 Noise monitor 18a Variable transmission path amplifier circuit 18b Receiver variable amplifier circuit 21 microphone 22 speakers L call line

Front page continued (72) Inventor Minoru Fukushima 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) Reference JP 62-51864 (JP, A) JP 51-139708 (JP, A) ) JP-A-59-230355 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04M 9/00-9/10 H04M 1/00 H04M 1/60-1/62

Claims (5)

(57) [Claims] 1. An intercom base unit including an intercom base unit and an intercom base unit, which are connected via a call line, wherein the intercom base unit is installed indoors, and includes a microphone, a speaker, and
And a voice switch circuit having a transmission channel variable insertion loss circuit and a reception channel variable insertion loss circuit for comparing the transmission signal level and the reception signal level and changing the loss amount according to the comparison result. The slave unit is installed at the entrance or the like and has a microphone and a speaker.In a loudspeaker communication device, noise that periodically detects the noise level on the doorphone slave unit from the microphone of the intercom slave unit during non-call The detection unit, the transmission line variable amplification circuit located after the transmission line variable insertion loss circuit, and the gain of the transmission line variable amplification circuit are changed according to the intercom subunit side noise level obtained by the noise detection unit. The transmission path gain varying means is
This is a voice call device that is installed on the main phone. 2. An intercom base unit and an intercom base unit, which are connected via a call line, the intercom base unit is installed indoors, and includes a microphone, a speaker, and
And a voice switch circuit having a transmission channel variable insertion loss circuit and a reception channel variable insertion loss circuit for comparing the transmission signal level and the reception signal level and changing the loss amount according to the comparison result. The slave unit is installed at the entrance or the like and has a microphone and a speaker.In a loudspeaker communication device, noise that periodically detects the noise level on the doorphone slave unit from the microphone of the intercom slave unit during non-call The receiver, the receiver variable amplification circuit located in the preceding stage of the receiver variable insertion loss circuit, and the receiver gain that changes the gain of the receiver variable amplifier according to the noise level on the doorphone handset obtained by the noise detector. Variable means and
This is a voice call device that is installed on the main phone. 3. An intercom base unit including an intercom base unit and an intercom base unit connected via a call line, the intercom base unit being installed indoors, and having a microphone, a speaker, and
And a voice switch circuit having a transmission channel variable insertion loss circuit and a reception channel variable insertion loss circuit for comparing the transmission signal level and the reception signal level and changing the loss amount according to the comparison result. The slave unit is installed at the entrance or the like and has a microphone and a speaker.In a loudspeaker communication device, noise that periodically detects the noise level on the doorphone slave unit from the microphone of the intercom slave unit during non-call Detecting section, variable transmitting path amplifying circuit located after the variable transmitting path insertion loss circuit, variable receiving path amplifying circuit located before the receiving path variable insertion loss circuit, and door intercom obtained by the noise detecting section A gain reciprocal variable means for reciprocally varying the gains of the variable transmission path amplifier and the variable reception path amplification circuit according to the noise level on the equipment side
A voice call device characterized by being installed in a machine . 4. When both the transmission signal level and the reception signal level are below a predetermined level, the loss amount of the transmission channel variable insertion loss circuit is maximized and the loss amount of the reception channel variable insertion loss circuit is minimized. 4. The loudspeaker communication apparatus according to claim 3, further comprising a sound collecting means for minimizing the gain of the variable transmission path amplifier circuit and maximizing the gain of the variable reception path amplifier circuit. 5. The gain of the transmission channel variable amplification circuit and the reception channel variable amplification circuit is minimized when the noise detection unit periodically detects the noise level on the intercom subunit side from the microphone of the intercom subunit when not talking. 5. The voice communication device according to claim 3 or 4, further comprising sound leakage prevention means.